Folding machine



' s Sheets-Sheet 1 Filed July 7, 1967 INVENTOR.

RALPH L. DAVIDSON ATTORNEYS Feb.17,1970 R. 1.. IDAVIDSOIN 3,495,819

FOLDING MACHINE Filed July 7, 3.967 I 3 Sheets-Sheet 2 XNVENTOR. RALPH L. DAVIDSON BYm L ATTORNEYS Feb. 17,1970 R. L. DAVIDSON 3,

' FOLDING MACHINE 3 Sheets-Sheet 3 Filed July 7; 1967 INVENTOR. RALPH L. DAVIDSON ATTORNEYS United States Patent 3,495,819 FOLDING MACHINE Ralph L. Davidson, Worcester, Mass, assignor to Curtis & Marble Machine Co., Worcester, Mass, a corporation of Massachusetts Filed July 7, 1967, Ser. No. 651,815 Int. Cl. B65h 45/20 U.S. Cl. 270-79 4 Claims ABSTRACT OF THE DISCLOSURE Background .of the invention The field of the invention generally comprises folders for textiles, and it more particularly relates to a folder oscillating or reciprocating between jaws to produce zigzag folds in a web of material. The folder is associated, at the supply end, with a scray automatically loaded in response to the Weight of material therein, and at the delivery end, with a table lowered automatically in such manner as to maintain the level of the top fold of the material at or near the level of the jaws.

Prior art machies generally have tables lowered in relation to the folding devices. Certain prior art machines also have the tables oscillating about horizontal axes in relation to fixed jaw parts to form and engage the folds laid down by the folder. These machines all have as an objective the provision of a fixed folding level in the machine, that is, a substantially constant level at the top of the pile of fabric. The table is lowered in a series of jogs to accommodate the increasing depth of the folded material. The machines differ widely, however, in the structures and characteristics of the jogging table drive controls. In addition, they differ in the means employed to maintain control of the clamping pressure on the jaw or gripper devices as the depth of the folded pile increases. In some cases, as in Patent No. 2,845,265, issued July 29, 1958 to R. S. Gamble et al., pneumatic means are employed, and in other cases the means are manually operated.

In still other prior art machines having a jaw part reciprocal about a fixed pivotal axis, it is apparent that while the table is stationary the pressure of the jaw on the pile progressively increases with each added fold. Also, the jaw is deflected increasingly by the folds when in its rest or nonoscillating and fold-engaging position. However, little if any attention has been given to the potential utility of means responsive to the jaw position at rest as an aid in controlling the jogging means or the working limits on the jaw pressure. It is noted that the movable jaw parts are oscillated or reciprocated to an extreme open position to receive each and every new fold, this extreme position being far beyond the rest position in which the jogging controls should preferably be operated. It is normally desired to lay down a substantial number of folds between successive jogs of the table, which requires control means that are not 0 erative for each and every fold, but only at substantially less frequent intervals.

3,495,819 Patented Feb. 17, 1970 In consequence, jogging or table drive means of varying reliability and complexity have been associated with other variables such as the weight or height of the folded pile, employing such variables to initiate the jogging table movements.

Summary The devices hitherto employed for controlling the accumulation of material in the scray and for jogging the table have not proven entirely satisfactory. It is an object of this invention to provide a largely mechanical and automatic electrical system of simple and reliable form that offers more precise adjustment and insures smooth and continuous performance of the machine with a variety of weights of textiles.

This invention attains the foregoing object by means automatically responsive to the weight of material at the scray or feed end, and responsive to the rest position of the movable jaw parts at the table or delivery end. More specifically, the peculiar advantages of a vaneoperated limit switch or analogous devices are utilized to this end, in conjunction with a blanking circuit enabling the vane switch to operate the table drive only when it is in the rest position as defined above.

Other features of the invention will be seen by reference to the following description of a preferred embodiment, and include certain improvements in the combinations of the parts and in their respective modes of operation.

Brief description of the drawing FIG. 1 is a side elevation of a machine embodying the invention.

FIG. 2 is a detail elevation of the table drive control jaw and related parts, shown in a rest position in which a jogging movement is initiated.

FIG. 3 is a schematic circuit diagram of the parts controlling certain operations of the machine.

Description of the preferred embodiment Referring to FIG. 1, the preferred embodiment of the folding machine is shown supported within a rigid steel main frame 12, preferably made up of channel irons, angle irons and beams of suitable cross section welded, riveted or bolted together in a conventional manner, for example as shown in said patent to Gamble et a1. For convenience in the following description, the machine supported on this frame may be considered as divided into three operative sections: a scray section 14, a folding section 16 and a table drive section 18. A web 20 of cloth to be folded is drawn into the machine intermittently from a supply roll, basket or other suitable supply means. It passes between a draft roll 22 and a nip roll 24 into a metal scray pan 26, where it accumulates until the total weight in the pan reaches a predetermined value as described below. The web passes over a bar 28, under a conventional tension control device 30, over a slide 32, and over a bar 34 where it enters the folding section 16.

In the folding section the Web passes between a pair .of oscillating, longitudinal angular metal folding blades 36 that draw it alternately to and between a pair of oscillating jaws 38 and 40. These jaws and the blades 36 extend the full width of the web 20. By the coaction of the jaws and the blades, the fabric is laid up on a table 42 in a pile 44 of fabric containing zigzag folds defining panels of precisely measured length, for example one yard, one meter or any desired folding dimension.

At periodic intervals the table 42 which is suspended upon chains 46, is lowered in jogs to accommodate the increasing height of the pile 44. As explained further be ow, the machine automatically stops after a program producing a pile of preselected height. The machine also has safety limit means under the control of a number of earns 48 mounted on the drive shaft 50 for the cables 46. The table drive job controls, hereinafter described in greater detail, are associated with the table drive control jaw 38, and include an oscillating cam 52 and a vaneoperated limit switch bvl having a part pivotal with the jaw 38 and providing an indication of its rest position upon the pile 44 after completion of each fold by the jaw 38. This control is further associated with a blanking device including a vane-operated limit switch pvl that prevents the oscillating movement of the jaw from producing undesired operations of the table drive means.

Referring more specifically to the scray section 14, the draft roll 22 is driven by a scray motor SM by means of a V-belt 58. The motor SM is energized intermittently under the control of the circuit shown in the upper part of FIG. 3, as further described below.

As in conventional machines, the draft roll 22 has a fixed pivotal axis in the frame 12 and the nip roll 24 has a spring support causing it to bear continuously upon and in rolling engagement with the roll 22. Thus the web 20 is drawn at a continuous speed into the scray pan 26 while the motor SM is running.

The pan 26 is supported on cross bars 60 and 62 extending between pivotal L-shaped scray frame members 64. The bar 60 is secured in the frame 12 and the scray frame members 64 pivot about the axis of this bar, thus pivoting the scray pan 26. One end of each of the members 64 is bent and threaded to receive a stop screw 66 that defines a lower stop or limit position of the scray pan by contact with the main frame 12.

An extension arm 68 bearing a 70 extends from one of the frame members 64, the pin 70 being in position for alternate operation of an empty scray limit switch esl and a full scray limit switch fsl, these switches being supported upon the main frame 12. By the means hereinafter more fully described in connection with the circuit of FIG. 3, these switches turn the motor SM on and off as required to keep the weight of fabric within the scray pan 26 within predetermined limits.

A tension spring 72 is secured at one end to a lateral extension of the members 64, and at the other end to the frame 12. When the scray pan 26 is empty, the spring 72 raises the frame members 64 and the scray pan sulficiently to cause the pin 70 to actuate the limit switch esl, turning on the motor SM. The motor runs continuously until such time as the weight of the fabric overcomes the tension of the spring 72 suniciently to allow the pin 70 to actuate the limit switch fsl. This turns off the motor SM which then remains off until sufiicient fabric is removed from the scray pan to permit the spring 72- to elevate the frame members 64 to the position where the limit switch esl is again actuated.

The web is withdrawn from the scrap pan by the folding blades 36, passing beneath a seam trip limit switch stl associated with controls hereinafter described for normally stopping the machine with a seam at or near the top of the pile 44. The blades 36 are very similar in action to the like-numbered blade in the said patent to Gamble et a1. They are fastened together in mutually parallel, spaced relationship at their ends by brackets 74 that are slidable on a pair of rods 76 pivotal at their upper ends in the main frame 12. The brackets 74 are also pivotal on a pair of arms 78 that are in turn pivotal at their lower ends on the main frame 12. Thus oscillation of the arms 78, which are respectively located on the sides of the machine, causes the blades 36 to reciprocate between two extreme positions, of which one extreme position is illustrated in FIG. 1. This oscillatory movement is imparted by a rod 80 pivoted on a bracket 82 fixed to each arm 78. A crank 84 is secured at 86 to the rod 80 and is pivotal about a shaft 88, the shaft being driven by a gear train 90, a V-belt 92 which drives the gear train, and a folder hlade motor FM= During the normal operation ofthe machine the motor FM rotates at constant speed:

A half-circular shaped metal vane 94 is secured to the shaft 88 and rotates, through a slot in the vane-operated limit switch pvl. This switch is associated with the blanking circuit in the table drive controls in a manner hereinafter described.

The mechanism described above oscillates the jaws 38 and 40 by means of the cam 52 and an identical cam 96, respectively pinned to shafts 98 and 100, to which the jaws 38 and 40 are also respectively pinned. The shafts 98 and 100 have bearings fixed to the frame 12. The cams 52 and 96 are engaged by cylindrical sleeves 102 on the brackets 74, and are each alternately pushed from a rest position in which the corresponding jaw bears upon the pile 44 to an upper limiting position illustrated by the cam 52 in FIG. 1. In the latter position, the jaw 38 has an end situated between the folder blades 36. The jaws 38 and 40 are resiliently urged toward the rest position, as shown in FIG. 2. The shaft 98 has a bracket 104 pinned to it, and the bracket 104 is attached to one end of a tension spring 106 secured at its other end to the main frame 12. The jaw 40 has an identical spring, not shown. As the folding blades 36 move from the position shown in FIG. 1 toward the front of the machine, the jaw 38 engages the fold and retains it, while the blades 36 withdraw a further portion of the web from the scray pan 26 and repeat the folding operation in cooperation with the jaw 40.

A metal vane 108 is secured to the shaft 98, this vane being located in position to pass through a slot the vane-operated limit switch bvl similar in construction to the switch pvl previously described. As shown in the lower portion of FIG. 3, these two switches are in series connection and are used for control of the table drive. Each of these switches includes a permanent magnet having a flux path including an air gap across the slot with which the vane is associated. The parts are so constructed that the switch has one position when a sufilciently large portion of the vane is within the slot, and another position when a smaller portion of the vane is within the slot. Details of the device are not given, as it is commercially available. FIG, 2 illustrates the position of the vane 108 at which the change of switch position occurs. In this position, the vane 108 has been sufficiently rotated out of the slot in the switch bvl by the pile 44 to reduce the magnetic flux to a point where the contacts move from a normally open position, as shown in FIG. 3, to a closed position. For a shorter pile 44, the vane 108 has a larger portion within the slot in the switch, whereby the magnetic flux remains at a sufficiently high level to prevent closure of the contacts.

The foregoing construction has the advantage that the change the switch position, which operates the table drive as hereinafter further described, is a function of the position of the vane and therefore of the jaw 38,

, and is not a function of the tension on the jaw. Thus the spring 106 can be adjusted for higher or lower tension to compress the folds more or less firmly, but the table drive will continue to operate when the jaw reaches the identical position shown in FIG. 2. This is useful for folding a variety of textiles of varying thickness surface texture, weight and hand.

As shown in FIG. 3, the scray motor SM and the folder blade motor PM are three-phase alternating current operated motors. The table drive, on the other hand, is driven by a direct current table drive motor TM. As shown in FIG. 3, this motor has a continuously excited single wave rectified field winding, although in practice it is preferred to vary the current this field so as to provide a normal slower speed for jogging table drive movement and a faster speed for dofling after a pile 44 has been completed and for return of the table to its upper limit position. The controls associated with these latter operations have been omitted from the drawing for the sake of simplicity.

The armature of the motor TM receives pulses of direct current from a pulse source PS, as further described below in connection with the circuit diagram. The motor TM is connected through a chain drive 110 to a worm gear speed reducer 112 driving a chain 114. The speed reducer provides a reduction of 60:1, whereby the motor may serve as a brake on the table motion and the weight of the pile 44 cannot reverse the motion of the table drive mechanism.

The chain 114 rotates the shaft 50 which carries sprockets 116 over which the chains 46 are received and also carries a number of control cams 48. These cams operate an extreme bottom limit switch ebl (FIG. 3) When the table 42 is in its lowest position within the main frame 12, a bottom safety limit switch bsl when when the table is in a position slightly above 'the extreme bottom position, and a program limit switch pl which is actuated when the table 42is in a position corresponding to a pile 44 of the desired height. This position is adjustable by rotation of the corresponding cam 48.

In addition to the illustrated cam-operated limit switches, there are other limit switches associated with the top limit positions of the table, which are used to limit the upward or reverse movement of the table drive after dofling, but these parts have been omitted from the drawing as immaterial to the present invention.

FIG. 3 schematically shows circuits for operation of the scray drive motor SM, the folder blade motor FM and the table drive motor TM. For simplicity, only certain parts of the entire circuit are shown. The parts omitted from the drawing are conventional and include the usual fuses, overload devices, electrical jog controls and remote controls. Also omitted from the drawing, as stated above, are the usual controls for doffing a completed pile 44 of fabric and for returning the empty table to the top position, including associated means for speeding up the table drive motor during this return movement.

In the drawing, relays are designated by capital letters, their corresponding contacts having the same letters in lower case, and being shown in the positions corresponding to the unenergized state of the relays. Limit switches are shown in their unactuated positions. The switch pvl is shown in its position retained throughout the oscillation of the jaw 38 during engagement of the blades 36 with the cam 52. The switch bvl is shown in its position corresponding to jaw positions lower than that of FIG. 2.

The machine is provided with three-phase alternating current power connected from lines p through a power switch ps. The motors SM and FM are three-phase motors, and the remainder of the circuit is supplied through a transformer t by reduction of the voltage in a single phase.

Operation of the machine is started by depressing a momentary start push button bb which energizes a start relay SR. A table drive relay TD is thereby energized through make contacts sr-l of the relay SR. While the button bb is depressed a down drive relay DD is also energized through make contacts sr3 of the relay SR, provided that neither the extreme bottom limit switch ebl nor the bottom safety limit switch bsl is actuated. Upon release of the push button bb the relay SR holds on its make contacts sr-2 and make contacts dd-Z of the relay DD.

The energized relays TD and DD prepare a circuit to the armature of the direct current table drive motor TM from the pulse source PS. This source is sold by General Electric Company under the name Statotrol Drive and is operated by alternating current, delivering pulsed direct current to the motor armature. It includes reference voltage connections ra, rb and re and pulse output connections pa and pb. The unit includes an internal circuit (not shown) to supply a constant reference voltage between the connections ra and rb. The connection rc comprises a pulse trigger circuit associated with the vane operated limit switches pvl and bvl, and is connected to the brush of a potentiometer P having its end terminals across the connections m and rb.

The field winding of the motor TM, as stated above, is separately excited through a rectifier 118 providing halfwave rectified current. As further described below, the armature of the motor TM is intermittently energized under the control of the trigger circuit which, when closed by the limit switches pvl and bvl, causes passage of a half-wave rectified voltage impulse through a rectifier 120, internal circuits of the pulse source PS and make contacts dd-l and td-2 of the relays DD and TD, respectively, these relays being already energized as described above.

The responsive downward movement or jog of the table 42 results from the acceleration of the armature and its subsequent deceleration and coasting to a stop. The total resultant vertical jogging movement is determined by mechanical inertial factors and also by the voltage applied to the trigger connection rc. This is controlled by adjustment of the potentiometer P which changes the voltage on the trigger connection rc so as to produce greater movements for thicker textiles and smaller movements for thinner textiles.

The table drive motor TM is stationary when a folding operation is started, and does not receive an impulse until the vane operated limit switches pvl and bvl are simultaneously closed. The switch pvl is closed only during a half-cycle interval when the jaw 38 is at rest on the pile 44 of fabric, that is, when the folder blades 36 are out of contact with the cam 52. It acts as a blanking device to prevent operation of the motor during oscillation of the jaw by the folder blades. The switch bvl is closed only when the vane 108 is removed from the magnetic circuit of the switch to at least the extent shown in FIG. 2.

The same depression of the start push button bb, described above, also initiates operation of a control circuit associated with the scray drive and folder motors SM and FM, respectively. A relay CR is energized through break contacts pr1 of a relay PR, and holds through contacts cr-l. This causes energization of a forward folding relay FF through make contacts cr-2 and break contacts rf-l of a reverse folding relay RF. The relay FF performs two functions, namely, energization of the folder motor PM by closure of contacts ff2, and preparation of the circuit of a scray drive relay SC by closure of make contacts ff-l.

The scray drive may now operate on an independent intermittent basis. Assuming that the scray pan is initially empty, the empty scray limit switch esl is actuated and the relay SC is energized, closing its contacts sc-Z to energize the scray drive motor SM, and holding on make contacts sc-l. The scray motor continues to run until the scray pan moves down under the weight of the fabric and against the tension of the spring 106 through a sufficient displacement to actuate the full scray limit switch fsl, deenergizing the relay SC and thereby deenergizing the motor SM. When sufiicient cloth is thereafter removed by the folder to permit the switch fsl to close again, the relay SC will remain unenergized until the switch esl is again actuated.

Means are provided to terminate the folding operation after the table has been lowered sufficiently to actuate the program limit switch pl, corresponding to a pile of the desired height. More specifically, the folder motor FM is abruptly stopped at the next movement after the switch pl is closed when a seam across the web is sensed by the seam trip limit switch stl and the folder blade has reached its forward limit of movement (the right-hand limit as viewed in FIG. 1). This permits the web to be severed at this seam preparatory to doffing, and causes the folder to commence the next pile with a rearward movement. This feature is desirable as a safety measure.

The foregoing operations are controlled with the aid of a centrifugal switch cs on the drive shaft of the motor 7 FM. This switch is closed whenever this drive shaft is rotating forwardly, and opens when the shaft is substantially at a standstill. The termination operation in detail is as follows.

At the first moment when the program limit switch pl and the seam trip limit switch stl are both actuated, a program relay PR is energized, holding on its make contacts pr-Z. This opens break contacts pr-l in the circuit of the relay CR, and this relay is deenergized at the next instant thereafter when the folder blades 36 have reached their forward limit (the right-hand limit in FIG. 1), opening a folder blade limit switch fbl operatively associated with the shaft 88. This in turn deenergizes the relay FF by opening the contacts cr2, thereby opening the contacts fi2 to the motor FM and closing contacts fi-3 to energize the reverse folding relay RF. The contacts rf-Z then close to produce a reverse phase connection to the motor FM. The motor then receives current for a brief interval until the reverse torque that it develops reduces the forward speed of the shaft to zero and causes the centrifugal contacts cs to open.

The machine is then ready for doffing. As previously stated, the circuit used for this function is not included in the drawing as it forms no part of the present invention. In operation, this circuit includes the usual means to deenergize the relay DD, which deenergizes the relay SR by opening the contacts dd-2 in its holding circuit. The table drive controlling relays are then all deenergized and the circuit is restored in its initial condition.

It will be recognized that various modifications in the machine may be carried out in accord with generally recognized practices, and without departing from the teaching of this invention. For example, with respect to the described means for oscillating the jaws 36, various other means may be employed to open the jaws and to allow them to close to a rest position on the pile 44. Similarly, the particular forms of limit switches and the circuits that they operate may be varied to the extent permitted by the teachings hereof.

I claim:

1. In a folding machine for a web of material, the combination of a table having a surface to receive the material,

a reciprocating folder for conveying the web to the surface in layers by feeding it alternately to and between a pair of mutually spaced jaw positions,

means for driving'the folder,

jaw means in each said position supported for pivotal movement and comprising a jaw adapted to engage the folds, means resiliently urging the jaw against the folds and a cam pivotally secured to the jaw and adapted for engagement and oscillation by the folder at the extremitiesof its reciprocating movement, at least one of said jaw means further having one part of a vane-operated switch device pivotally secured to the jaw, said switch device having contacts, another part of said switch device being supported in fixed position, said switch device parts including a magnet and a vane movable within the magnetic field thereof and adapted to operate said contacts as a function of the position of the vane within said field,

motor driven means for intermittent downward movement of the table in relation to the jaw positions, and

an electrical circuit connecting said contacts and motor and adapted to transmit a pulse of electrical energy to the motor in response to operation of said con tacts.

2. The combination according to claim 1, in which the pulse is adjustable to jog the table downwardly a predeterparallel folder blades slidably mounted on the guide member and retaining the web.

References Cited UNITED STATES PATENTS 2,098,427 11/ 1937 Menschner 27079 2,152,399- 3/ 1939 Collier et a1. 27079 2,845,265 7/1958 Gamble et a1. 27079 3,083,008 3/1963 Miller 27079 X LAWRENCE CHARLES, Primary Examiner 

